1. Field of the Invention
The present invention relates to a fixing apparatus and image forming apparatus by which a toner image transferred onto a paper sheet by an electrophotographic process or the like is fixed on the sheet.
2. Description of the Related Art
Recently, many fixing devices have a plurality heater lamps in a heat roller. In such a fixing device having a heat roller containing a plurality of heater lamps, thermostats are installed in one-to-one correspondence with these heater lamps in order to prevent inconveniences caused by abnormal lightning of the heater lamps.
Also, some conventional fixing devices use a plurality of different types of thermostats having different operating temperatures corresponding to predetermined installation positions on the surface of the heat roller. In a fixing device like this, each thermostat must be correctly identified and installed in a predetermined position. For example, when a plurality of thermostats having the same shape but different in operating temperature are to be installed, each thermostat may be attached to a wrong position because all the thermostats have the same shape. To solve this problem, each thermostat having undergone processing such as marking for correctly identifying it is installed in a predetermined position. Unfortunately, in the fixing device as described above, this processing of marking each thermostat increases the number of thermostat mounting steps, thereby increasing the cost of the fixing device.